1. Field of the Invention
The present invention relates to a machine tool having a stopper that prevents chips from entering the machine tool while it is used.
2. Description of the Related Art
Machines tools are generally structured so that a protective cover is installed over their driving parts and their surroundings in order to prevent chips generated during machining from accumulating on the driving parts and their surroundings.
According to a disclosure in Japanese Patent Application Laid-Open No. 2007-61952, a feed screw and a linear motion guide, which are used to drive a saddle in a front-rear direction of a machine tool, are protected from chips by a protective cover installed over the saddle. The protective cover installed over the saddle moves in the front-rear direction in conjunction with the motion of the saddle, and enters and leaves a space under a column to prevent chips from accumulating on the feed screw and the linear motion guide. Further, a wiper is mounted on the column to scrape off the chips accumulated on the protective cover. When the protective cover moves in the front-rear direction, the wiper removes the chips accumulated on the surface of the protective cover.
Meanwhile, when the protective cover moves in conjunction with the saddle, a certain clearance needs to be provided between the protective cover and the linear motion guide and the linear motion guide mounting surface to prevent the interference. Hence, the chips may accumulate on the linear motion guide mounting surface, parts near the linear motion guide mounting surface, or the linear motion guide.
When the protective cover moves toward the column in conjunction with the saddle, the accumulated chips may be pushed by the protective cover and moved on the linear motion guide mounting surface or the parts near the linear motion guide mounting surface. However, no member is provided to block the movement of the chips that are pushed by the protective cover. As a result, the chips drop into a space formed under the column (the space for accepting a part of the protective cover). Another problem is that the chips are left accumulated on the linear motion guide mounting surface, the parts near the linear motion guide mounting surface, or the linear motion guide.